In mobile radio networks, the possibility of transmitting an emergency call automatically, in addition to the manual dialing of an emergency call number, has become increasingly established in the last several years. This service is referred to as “emergency call” and effects an automatic connection between a mobile telecommunications device and a so-called LCS client; in other words, for example, an emergency call center. For this purpose there can be provided, in motor vehicles for example, an accident sensor which, upon detecting an accident,—automatically (possibly after interrogating the reaction of the-driver) initiates the emergency call. At the same time it also must be possible to pinpoint the location of the vehicle if, for example, the driver is unconscious. For this purpose there is provided in, for example, the UMTS (Universal Mobile Telephone System) standard an interrogation procedure with the aid of which, when an emergency call is transmitted, it should be possible to locate the mobile telecommunications device even without any action on the part of the user.
Even apart from the emergency call there may be circumstances in which it is desirable to pinpoint the location of a mobile telecommunications device.
A method for transmitting an emergency call from a mobile radio subscriber device to an emergency call center in a PCS 1900 mobile radio system is known from WO 97/23104, wherein upon a request for emergency assistance (e.g. by entering an emergency call number such as “9-1-1”), position data of the mobile radio subscriber device may be transmitted.
An emergency call method in a cellular telecommunications system is known from U.S. Pat. No. 5,388,147, wherein position data of the calling mobile radio device is transmitted to an emergency call center only after setup of a digital transmission channel.
An object of the present invention is to enable the location of mobile telecommunications devices to be determined more quickly.